Since we were learning about the heart and lungs, we went over how the heart is a pump that pumps the blood around the body. The blood carries oxygen so that our muscles can work. We also talked about how your muscles need more oxygen when they're working harder, so you heart has to pump faster. The Magic School Bus Lost Works Out was a good episode for talking about the role of oxygen in the muscles and why the blood needs to circulate (on Netflix).

Changing Heart Rate

Materials:

Stethoscope

Timer

Place to write results

Procedure:

We started out by using our stethoscope to measure our resting heart rates. I did it by setting the timer for 30 seconds and multiplying by two. You could also go ahead and do the whole minute if it would be less confusing for your little one. Once we wrote our resting heart rates down, it was time for some exercise! Xander ran around in circles, did jumping jacks and stayed really active for a 3 minutes and we took his heart rate again. Then I exercised for the same amount of time and we took my heart rate. When we were all done we compared the results.

(We'd been to a party that day, hence the Batman face painting)

The Conversation:

I tried to ask Xander what he noticed about the numbers, and help him get to the idea that the active heart rates were faster than the resting. Then I asked him why the heart would need to pump faster (more times every minute) when we are moving than when we are resting. I helped lead him to the idea that the muscles are working harder, so need more oxygen.

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